1. Field of the Invention.
The present invention relates to drive systems in photographic processors. In particular, it relates to apparatus for securely retaining a gear on a drive shaft of a drive system in a photographic processor.
2. Description of the Prior Art.
In photofinishing, it is typical to continuously process long webs of photosensitive material by transporting the web through a series of processing tanks which contain different chemical solutions, and then through a dryer that dries the web. Both photographic film and photographic print paper are commonly processed in this manner.
In the case of photographic film, it is typical to splice together individual strips of undeveloped photographic film for processing. Cine processor machines are used to develop continuously the long webs of photographic film formed by splicing the individual strips of film.
In a cine processor, the film web is transported through the tanks by sets of transport rollers. One successful type of transport system used in cine processors is known as the "cradle drive" system. In this system, each tank has a transport rack with an upper and lower shaft on which are mounted a plurality of transport rollers. A drive shaft near the bottom of the rack engages edges of the lower set of transport rollers. This drive shaft is driven through a gear train by the cine processor drive system. The film web enters a transport rack on one side, and is transported in a spiral manner between the upper idler rollers and lower driven rollers of the rack until it reaches the other side of the rack, where it is transferred to the next transport rack.
As is easily apparent, any malfunction in the processor drive system results in costly downtime and possible damage to the photosensitive web. An important component of the drive system is the gears that transfer power from a main drive shaft to the drive shafts of the transport racks. The gears must be made of a material that is resistant to chemical attack from the various chemical solutions used in the processor.
Of particular importance is the manner in which the gears are attached to their respective shafts. In the past, any vibration present in the drive systems of cine processors has tended to loosen the set screws holding the gears on the shaft. Unless periodic maintenance checks are performed and set screws retightened as necessary, breakdowns of the drive system are likely to occur. This periodic inspection of the set screws is time consuming and inconvenient, particularly since lower gears typically are not easily accessible. They are, however, extremely critical and important. A relatively large number of gear assemblies are normally employed in a photographic processor. Also, in equipment used to process original film, failure can cause the loss of a significant quantity of irreplaceable material. Obviously, these risks become greater as the size and capacity of processors increase.